Optimizing systemic insecticide use to improve malaria control

Abstract

9Long lasting insecticidal nets and indoor residual sprays have significantly reduced 10 the burden of malaria. However, several hurdles remain before elimination can be achieved: 11 mosquito vectors have developed resistance to public health insecticides, including 12 pyrethroids, and have altered their biting behaviour to avoid these indoor control tools. 13 Systemic insecticides, drugs applied directly to blood-hosts to kill mosquitoes that take a 14 blood meal, offer a promising vector control option. To date, most studies focus on 15 repurposing ivermectin, a drug used extensively to treat river blindness. There is concern that 16 over-dependence on a single drug will inevitably repeat past experiences with the rapid 17 spread of pyrethroid resistance in malaria vectors. Diversifying the arsenal of systemic 18 insecticides used for mass drug administration would improve this strategy's sustainability. 19Here, a review was conducted to identify systemic insecticide candidates and consolidate 20 their pharmacokinetic/pharmacodynamic properties. The impact of alternative integrated 21 vector control options and different dosing regimens on malaria transmission reduction are 22 illustrated through a mathematical model simulation. The review identified drugs from four 23 classes commonly used in livestock and companion animals: avermectics, milbemycins, 24 isoxazolines, and spinosyns. Simulations predicted that isoxazoline and spinosyn drugs were 25 promising candidates for mass drug administration, as they were predicted to need less 26 frequent application than avermectins and milbemycins to maintain mosquitocidal blood 27 concentrations. These findings will provide a guide for investigating and applying different 28 systemic insecticides to achieve better mosquito control strategies. 29 30 Significance: 32 The widespread use of long lasting insecticidal nets (LLINs) and indoor residual spray 33 has selected for mosquitoes that are resistant to pyrethroids or avoid exposure by feeding 34 outdoors or on livestock. Systemic insecticides, drugs that render a host's blood toxic to 35 feeding mosquitoes, could be an effective control strategy for mosquitoes with pyrethroid 36 resistance and/or outdoor feeding tendencies. Here, a number of existing systemic insecticide 37 candidates are identified and their pharmacokinetic properties in different drug-host-route 38 scenarios consolidated. These data were used to parameterise a mathematical model that 39 illustrated the projected gains achievable in malaria control programmes already employing 40 LLINs. The findings provide a guide for investigating and applying different systemic 41 insecticides to improve mosquito control strategies and reduce malaria transmission. 42 Introduction: 43 Long lasting insecticidal nets (LLINs) and indoor residual sprays (IRS) have played 44 significant roles in reducing the burden of malaria (1, 2). However, several hurdles remain 45 before elimination can be achieved. First, pyrethroids are heavily used in LLINs and, 46 previousl...

Veterinary endectocides for malaria control and elimination: prospects and challenges

“…This idea is currently supported by semi-field data [27,28] as well as modelling for malaria [29], which predicts important reductions in transmission with the treatment of pigs [30] or cattle [31,32]. Here again, the models also predict remarkable reduction of transmission for other vector-borne diseases such as Chagas [33] and human African trypanosomiasis [34,35].…”

Control de Aedes (Stegomyia) aegypti utilizando Bacillus thuringiensis var. israelensis en Armenia, Quindío, Colombia

“…Una aproximación a este abordaje es el empleo de modelos matemáticos, los cuales, permiten hacer predicciones del comportamiento a corto, mediano y largo plazo, sin necesidad de trabajo experimental (Momo & Capurro, 2006). Así, el uso de datos obtenidos en campo o laboratorio, particularmente las concentraciones letales 50 y 95 del producto de interés, que posteriormente son incorporados a modelos matemáticos, permiten simular el uso de estas concentraciones en tiempos específicos (Meredith et al 2019), por tanto, diseñar estrategias de control del mosquito A. aegypti y así prevenir el dengue, el chicunguña y el Zika.…”